Like the title says I'm having an issue the past few days where I can't drive this truck more than a few miles before it starts acting up with rough idle at stoplights/sign and sluggish acceleration until it gets over 1200+rpm.

Cold starts fine, drives good till engine warms up to around 130+ECT then it starts acting up. Stumbles on acceleration for little bit and puts out a little black smoke until it gets moving. No check engine light or codes found.

However a month ago I had the check engine light come on with a P0404 & P0405 and it still started & ran/drove great even towing. If I reset the code it would stay off until I restarted the engine the next time. I replaced the Dorman EGR because it had a lifetime warranty and only had 5,000 miles on the first one. The code did not go away until about two weeks ago the light went off on the dash and has never come back but I had not erased the code? So I'm not sure if this is still lingering issue or what.

I was checking my ScangaugeII when I came back home today while the engine was still idling rough and this what I saw for Numbers:

Low idle in Park
ECT 193
EOT 191
FICM 49.0
IPR 21.4
ICP 582
ICV 0.81
V 13.8
TFC 1.91
VSS(fan speed) 0

(this one doesn't seem right in the past is 500 or more rpm from what I remember?)

What am I missing to check over?

 

You either have a short or a bad EGR Valve. Wiggle the wiring harness also look at the wires at the plug for a break. With scangauge you can't command the opening or closing.

 

I checked the harness this afternoon and couldn't find any issues and moving wires didn't seem to change anything. I was wrong about the fan speed I read the VSS not the FSS which did show an RPM and I saw the fan spinning while it idled today. Their is a lifetime warranty on the Dorman EGR valve so I exchanged it for a new one tonight thinking it was defective.

My test drive didn't get me far after that before it started running rough again.

I'm not sure what else to check other than tomorrow try that bubble test in the secondary filter bowl. Not sure if it's a bad injector... that is okay cold but goes bad as the engine warms up?

 

I've seen so many of those dorman egr valves,,, And I've yet to see one actually fix a truck long term. Normally it's a 1-3 day fix. But if the intake is sooted bad,, I've seen those valves last only a couple miles. If the egr system is needed,, time to disassemble and clean. Meaning intake off.

 

I won't be buying any more Dorman products after this ordeal. The auto parts store manager hassled me yesterday about bringing it back and exchanging it for another. Time to just bite the bullet and buy OEM like I should of done the first time.

Definitely wished I'd cleaned the manifold when I had it off this summer for the EGR & Oil cooler replacement. The part under the EGR valve doesn't have much build up but who knows in the parts you can't see what the build up might be like. The IA2 sensor was crusty when I cleaned last week.

 

but I noticed you have a low IPR reading replacing that should fix the issue (go with oem) I've had several Dorman and other aftermarket IPR s fail....

good luck please let us know if it was it.

 

The post is from October 2016...

IPR of 21.4% is near perfect for idle. On a fully warm truck 21-23% is good, indicates no internal high pressure leaks. ICPV is also .81v another reading on the money as the truck needs .80v to run and the ICP (desired) should be somewhere from 580-650, his is 582.

Noticed this was your first post, welcome to the site. Where in Cali are you from? We have some great members there, be sure to check out the state chapter forum and introduce yourself.

 

MadMan23 in my case it turned out to be a bad injector on the Drivers side bank, 3rd cylinder from the front. I replaced all on the driver's side since I was in their but that one had some diesel fuel that sprayed out when I was using compressed air to clean out the holes before putting new injectors back in.

So it must of had some mechanical failure because it never threw a code electronically. Had I known more before hand... earlier in the year I could smell diesel on the dipstick but it never "made" any significant oil. But that was my warning sign prior to this I guess, next time I'll know to bubble/balloon test sooner.

Truck runs great since the replacement. Just got back from a week and half camping trip out west with the travel trailer and that worked it good but it doesn't seem to mind. Sure does pull heavy well.